Calculate Circle Area using Java Example

/*
	Calculate Circle Area using Java Example
	This Calculate Circle Area using Java Example shows how to calculate 
	area of circle using it's radius.
*/
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
public class CalculateCircleAreaExample {
 
	public static void main(String[] args) {
 
		int radius = 0;
		System.out.println("Please enter radius of a circle");
 
		try
		{
			//get the radius from console
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			radius = Integer.parseInt(br.readLine());
		}
		//if invalid value was entered
		catch(NumberFormatException ne)
		{
			System.out.println("Invalid radius value" + ne);
			System.exit(0);
		}
		catch(IOException ioe)
		{
			System.out.println("IO Error :" + ioe);
			System.exit(0);
		}
 
		/*
		 * Area of a circle is
		 * pi * r * r
		 * where r is a radius of a circle.
		 */
 
		//NOTE : use Math.PI constant to get value of pi
		double area = Math.PI * radius * radius;
 
		System.out.println("Area of a circle is " + area);
	}
}
 
/*
Output of Calculate Circle Area using Java Example would be
Please enter radius of a circle
19
Area of a circle is 1134.1149479459152
*/